Party-line telephone system



(No Model.\ 2 Sheets-Sheet 1.

W. H. HARTER. PARTY LINE TELEPHONE SYSTEM.

No. 584,352. Patented June 15,1897.

TELEPHONE. N9 8..

TELEPHONE N. 1

R\ INVENTD'H'.

AT'TEET E3? Eh AIrTY (No Model.) 2 Sheets-$116M; 2.

1 W. H. HARTER. 1 PARTY LINE TELEPHONE SYSTEM.

No. 584,352. I Patented June 15, 1897.

IN VENTIZIF? \VILLIAM H. HARTER PATENT OF NORXVALK, OHIO.

PARTY-LINE TELEPHONE SYSTEM.

SPECIFICATION forming part of Letters Patent No. 584,352, dated June 15,1897.

Application filed August 10, 1896 To aZZ 2071,0122, it ill/a7 concern-.-

Be it known that I, VILLIAM H. HARTER, a citizen of the United States,residing at Norwalk, in the county of Huron and State of Ohio, haveinvented certain new and useful Improvements in Party-Line Telephones;and I do hereby declare that the following is a full, clear, and exactdescription of the invention, which will enable others skilled in theart to which it appertains to make and use the same.

My invention relates to the'selective ringing of substation-telephoneson what is generallyknown as a party-linei. 6., two or more subscribersstations connected to a single wire or circuit-and the object oftheinvention is to provide means whereby any one party or telephone 011such party-line circuit can be called by the operator at the centralstation without calling or disturbing any of the other parties on thesame circuit, at the same time unlocking the particular telephoneselected for talking while all the others remain locked out, thuspreventing any possible interruption by them while the one that has beencalled is in use.

Figure l is a diagrammatic view of my arrangement of circuits and parts,showing two telephones on one line and two corresponding sets of keys atthe central station or operating end. Fig. 2 is a similar View, butshowing only one telephone and one key, the position of the variousparts being shown as when a party is being called. Fig. 3 is a detail ofa harmonic vibrating magnet.

These illustrations serve to show What I have found to be simple andeffective means for selecting or calling any one of a number oftelephones on what is technically called a party-line without disturbingor ringing the other bells on the same circuit. Then as an additionaladvantage a lock-out arrangement is added to the selective device, bymeans of which it is within the control of the operator to lock out allthe other parties on the line who have not been called or selected fortalking, thus insuring strict privacy of communication betweensubscribers, and thereby making the service quite as efficient andsatisfactory as on independent lines-4. e. a separate and distinctcircuit for each telephone. The advantages of a line of Serial No.602,212. (No model.)

this kind over a single or independent line in point of economy arenumerous, afiording a very material cheapening in line construction,switchboard capacity, operating force, and other ways obvious topractical men, and thus enabling telephone-service to be furnished tosubscribers at rates that are within reach of a much larger circle ofusers and yet at a proportionately larger margin of profit to thecompany operating the plant.

The principle of selection involved in this device is the contemplatedunity or harmony of action between the two corresponding reeds at thecentral and the sub stations, and the construction and operation is suchthat when any one of the reeds at the central station is set intovibration its corresponding reed at the substation, on the line withwhich the central-station reed may be temporarily connected, willrespond with action. The corresponding reeds must be tuned to the samepitch, so that there will be isochronous action between them, so long asthe central-station reed is continued in vibration, and this ascertainedharmony controls in the selection. This fact has been practicallydemonstrated in the application of the principle to other electricaldevices and therefore requires no further substantiation.

What is claimed as novel in this invention is the special arrangement oradaptation of the principle, in the manner described hereinafter, to theselective ringing of telephonebells on a party-line.

In Fig. 1 I show two telephones, No. 1 and No. 2, on the same line orcircuit, and each spectively, are of the same fundamental tone or pitchand have the same vibratory actionthat is, they vibrate in harmony withthe same telephone can be connected with its corre- .tension m intocontact at H, p, and w.

number of vibrations per second. Telephone No. 2 has similar selectingdevices, but with the exception that the reeds a and b, respectively,are of a different tone or pitch from a and bthat is, with a greater orless vibratory action than in telephone No. 1. These reeds a and bareshown here as being a trifle longer than reeds a and b to indicate thedifference between the two; but in reality it requires but a littlemodification in size or weight to vary the harmonic pitch or vibratoryaction of the reeds in the various telephones.

The calling or selecting of one telephone among two or more on a line isdone by the operator at the central by merely plugging in andestablishing a circuit between the exchange apparatus and. the line andthen depressing the key 0 to close the circuit which operates theselective device. By this operation the various parts are set in motion,and in turn a new or branch circuit is established at the substation forringing the call-bell and at the same time unlocking the telephone,(which was locked when the operator inserted the plug into theline-socket by the operation of the central-office-battery currentthrough the back contact on key 0,) so that the subscriber called canopen communication on the line. The various circuits and the parts theyoperate are as follows:

First. The circuit which is established by depressing the key 0 atcentral to operate magnet A and which attracts reed a to make contact atcontact-point c. This initial circuit is indicated in Fig. 1 by arrows1.

Second. The circuit established by reed a and contact 6 and shown byarrows 2. This circu-itextends from central to the telephone called,whichever one it may be, and, assuming that it is to No. 1, it is alongthe arrows 2 2v and transmits rythmical impulses of current, which whenof just the right period and duration serve to operate electromagnet Band reed 1).

Third. The circuit shown by arrows 3 and created by the Vibrating reedZ) coming into contact with the contact-springfi This circuit isestablished to operate electromagnet l by the local (telephone or other)battery 7t for the purpose of attracting the armature ex- These contactsserve to simultaneously establish the fourth, fifth, and sixth circuits,which are shown in Fig. 2 for greater convenience and to avoidconfusion,though present in Fig. 1.

Fourth. The fourth circuit (shown by arrows 4:) is established atcontact at and armature extension 'm and serve as a path or branchcircuit for transmitting the ringingcurrents from the line D to thecall-bell 0 of the telephone.

Fifth. The fifth circuit (shown by arrows 5) is established by armatureextension on and contacts nand p and serves to maintain thelocal-battery circuit through the electro magnet Z, keeping the armatureextension 'm the one which has been called.

, the key 0 depressed.

Fig. 1.

in contact at n, p, and w, and this serves to keep the call-bells incircuit on line 4 and continuing until the local circuit 5 is broken atthe central station for communication, and

is shown by arrows 7 in Fig. 1.. This circuit 7 is for the purpose ofkeeping a current flowing through the lockingina-gn'ets v of theuncalled telephones to look all the hooks g, so

as to prevent any of the uncalled telephones being used or intrudingupon or interrupting This circuit 7 is shunted, as described, overcircuit 6 in the telephone that has been called, and thus all thetelephones but the one called are lockedout. lNhen the subscriberremoves the receiver h from, hook g, contact is broken at j and all thecircuits with the exception of 7 are broken, the various parts returningto their first or normal position.

Circuits 1, 2, and 3 are of but a few seconds duration, or just so longas the operator keeps Circuits 4:, 5, and 6 continue until thesubscriber removes the receiver from the hook to open communication overthe line. tor disconnects the line at the central station Circuit 7 ison until the operaby removing the plug from the line-socket.

Now, having separated the several circuits and indicated their function,the operation will be clearly understood and is as follows: Suppose, forexample, the operator at the central office hasa call for telephone No.1.

She plugs in on that particular party-line and then depressesthe key 0,which completes or closes the circuit indicated by arrows 1 in Thiscircuit extends through reed a to contact (I, which is the normalcontact-point of said reed, and thence by the arrows 1 to =coil A. Saidcoil in turn attracts reed ato it self and establishes contact at e andthereby completes circuit 2. cut off from the coil A on line 1 the reedCt will springback to its normal position against con Then as thecurrent is tact d, and the operation will be repeated and continued solong as the operator keeps the key a depressed and circuit 1 closed.Each vibration of the reed a will make contact at e, and a momentaryimpulse of current from the battery C will be transmitted over the line2 to the substation-magnet B, and the reed I) being in harmonic sympathywith reed a each successive impulse of current will produce acorresponding pull 011 reed hat regular intervals and in synchronismwith the vibrations ICO IIO

70 at j when the subscriber removes the receiver feature abovedescribed.

of reed a, thereby augmenting the range of motion of the reed 1) untilthe contact f is reached. hen the vibrations of reed b have attained asufficient range of movement to make contact at f, the local circuit 3is momentarily closed. The local circuit 3 extends from contact f overline 3 through the telephone hook or support arm g, holding the receiverh, thence through contact j, line 3,10- cal battery 7% magnet l, andback through the reed b to contactf. This circuit sends the current frombattery 7.", throughthe electro- I-nagnet Z, attracting the armature ofthe same and thereby closing the local circuit 5 and maintaining itindependently of contact f, and at the same time establishing andmaintainin g the ringing or calling circuit 4 through the contacts andlines shown in Fig. 2. This so continues until the receiver is takenfrom the hook by the subscriber and the circuit is interrupted atj. henthe armature of magnet Z is attracted, its extension m makes contact atn for the ringing-circuit on line at. This circuit extends from theproper generating source at the central office through the key 0, orotherwise, over line at to the callbells e and back over the line tocentral, the local circuit extending over lines 5, through local battery70, contact j on receiver-hook 9, through armature extension m atcontacts a and 1), over line 5, through electromagnet l, and back tobattery 7t", causing the magnet to hold armature down and keepingcontacts a and 2) closed, thus providing a continuous ringing-circuitover line 4 until the receiver 71, is removed from the hook g. The hookis then drawn up by the spring 0' and contact is broken atj. Thisrestores the various parts to their original or normal position and thesubscriber is free to communicate over the line.

\Vhen two or more parties are on a single line, it occasionally happensthat two of them desire to use the line at the same time; but as thiscannot be done it is desirable to lock out all but one or any twointercommunicating on the same line, so that strict privacy ofcommunication can be had. Such a device or arrangement constitutes apart of my invention, in combination with the selegtive The arrangementand operation of the deviceis as follows: After the key 0 at the centralhas been depressed and the various parts of the apparatus at thesubstation have operated the key is permitted to assume its normalposition against contact A circuit will be established extending fromthe oitice-battery C, over line 4, to main line D, where it will divideinto branch circuits through the various telephones on the line, asshown by arrows 7 in telephone No. 2, Fig. 1. This circuit 7 passes fromthe main line D to the magnet t at the substation and back again to themain line through electromagnet B. The magnet 11 attracts the armatures, which is provided with a hook or stop adapted to engage directly withthe arm of the receiver-hook while the latter is in its normal positionof rest with the receiver 72 on its hook, thus locking the receiver-hookandpreventing its going up and making contact at t for communicationover the line. This operation is the same for each telephone on theline, except in the case of any one having been selected for talking,which latter condition is shown in Fig. 1. This one must remain unlockedwhile the others are locked, and this is done by shunting the currentaround or past the locking-magnet t in the telephone called, permittingits armature to be drawn back bythe spring and out of engagement withthe telephone-support arm. This shunt-circuit is shown in Fig. 2 and isformed by the line 6, contact to, and armature extension m, with thelatter down as when that particular telephone has been selected orcalled, as hereinbefore described. hen the receiver is taken from thehook and the latter is drawn up by its tension spring, the local circuit3 is interrupted at j and the original condition of the line restored.When through talking, the subscriber gives the usual rin -off si nalwhereu on the operator at the central withdraws the plug from theline-circuit, disconnecting it from the battery, and thereby unlockingall the telephones on that line and permitting a fresh call to be madefrom any of the substations.

In Fig. 3 an enlarged detail is shown of one of the reed magnets and itscontacts. Any change in structure or design in the magnets may be made,of course, and a tuning-fork may be substituted for the musical reed, asany special design of the magnets may suggest, without affecting theidentity or spirit of the invention. The reed-magnet contacts are hereshown as screws having conical springs at their ends, but these mightalso be changed. The object of the coneshaped spiral-spring contact isto maintain the con necti'on long enough to overcome the inertia and tomore certainly operate the armature of the electromagnet Z, the spiralbeing of such weight and elasticity as to follow the motions of the reedwithout materially affectin g the uniformity of its vibrations. Thecontact f of reed I) must of necessity be so adj usted that contact ismade only after several vibrations of the reed have taken place and itsamplitude sufficiently increased. This would necessarily occupy but avery small fraction of a seconds time. Each impulse of current on theline from the transmittingbattery C will tend to vibrate all the reedson the line, but in accordance with the wellknown law of harmonics thatparticular reed only which is of the same fundamental tone or pitch asthe corresponding transmitting-reed will respond with action or increasein amplitude,

and thus make contact at f for operating the local circuit andapparatus.

I claim-- 1. In a telephone party-line harmonic se lector signalingdevice, the combination of a IIS normally-closed main or line circuit;an electromagnet and a Vibrating reed-armature at the central station,and a key for connecting the same with the line-circuit, a correspondingelectromagnet and reed-armature at a substation adapted to close anindependent local-battery circuit; an electromagnet in said localcircuit having a contact-making armature adapted to automatically closeand maintain the local-battery circuit within itself and as a shuntaround or past the reed-armature contact, substantially as described.

2. In a telephone party-line harmonic selector signaling and lock-outdevice, the combination at the substation of an electromagnet withvibrating reed-armature adapted to Vibrate in unison with acorresponding reedarmature at the central station; a circuitclosingcontact on said reed-armature capable of closing, under ample vibration,a localbattery circuit independent of the line-circuit and of which saidreed-armature constitutes a part; an electromagnet with contactarmatureincluded in said local-battery circuit responsive to current impulsesfrom the local battery on momentary contact of said reed-armature, andsaid contact-armature adapted to close and maintain the local-batterycircuit within itself independent of said reedarmature, substantially asdescribed.

3. In a telephone party-line harmonic selector signaling andlock-outdevice, the combiation atthe substation of avibrating reed.- armature, alocal-battery circuit, the telephone-support arm included in saidlocal-battery circuit and adapted to open or break said local circuit byremoving the t'eleph0ne-' receiver from the hook, an electromagnet andcircuitclosing armature included in said 10- cal circuit and adapted toclose and maintain the local circuit within itself, through andincluding said telephone support arm, substantially as described.

4. In a telephone party-line harmonic selector signaling and lock-outdevice, the combination at the substation of an electromagnet having acircuit-closing reed-armature in the main circuit, a local-batterycircuit, the telephone-receiver support-arm and'an electromagnet withcontact-making armature included in said local circuit,saidcontact-armature adapted to close and maintain a shunt to the main'orline circuit through and including the ordinary telephone-bell,substantially as described.

5. In a telephone party-line harmonic selector signaling and lock-outdevice the combination at the substation of an electromagnet withreed-armature, a local-battery circuit, an electromagnet withcontact-making armature included in said local circuit actuated bycontact makes of the said reed-armature, said. contact-armature adaptedto not only close and maintain the local circuit within itself but alsoto establish and maintain a new or shunt circuit to the main linethrough and including the ordinary telephone-bell, or other signalingdevice, substantially as described.

6, In a telephone party-line harmonic selector signaling and lock-outdevice the combination of anormally-closed main-line-circuit, a constantcurrent flowing in said circuit when connected at the central stationfor talking, an electromagnet with reed-armature at the substationincluded in said main line circuit, a separate electromagnet -with ahook or locking-lever armature connected in series with the saidreed-armature electromagnet in the main-line circuit, said separateelectromagnet responsive to said constant current, the ordinarytelephoneadapted to directly engage with and prevent the raising of saidtelephone fork or support arm so long as it is actuated by the mainlinecurrent, substantially as described.

7. In a, telephone party-line harmonic selector signaling and lock-outdevice the com- ;bination of a normally-closed main-line circuit, aconstant current flowing in said mainline circuit, the ordinarytelephone-support arm, an electromagnet with locking-lever argmatureadapted to engage directly with said telephone-snpport arm while in itsposition 30f rest with the telephone in its place, a local orindependent battery circuit, anelec- Etromagnet with reed-armature inseries with {said locking-electromagnet in the main-line i'circuit, saidreed-armature adapted to close isaid localcircuit, a third electromagnetwith :circuit-closing armature included in said-lo- ;cal-battery circuitand responsive to the action of said reed-armature, whereby it closes helocal circuit upon itself, a shunt orbridge icontact on said circuitclosing armature, which, when closed, diverts or shunts the main-linecurrent away'from or past the lockiing-eleotromagnet, permitting itslocking-armature to be withdrawn from engagement fwith thetelephone-support arm and thereby unlocking the telephone, substantiallyas described.

Witness my hand to the foregoing specification this 1st day of August,1896.

IVILLIAM H. IIARTER. I

IVitnesses:

E. G. BOUGHTON, LENA M. BOUGHTON.

support arm or fork, said locking-amnature IIO

